The priest paused after finishing a prayer, looked at someone off to his side and scratched his forehead.

“We had something happen,” he told the congregation.

The Rev. Joseph Crowley paused again, video shows.

“It’s hard to say, actually,” he added.

What happened, some at the Connecticut parish now say, was a miracle: During Communion, a bowl holding the hosts – the wafers that Catholicism teaches are transformed into Jesus Christ’s body during the Mass – began to run out. And yet, Crowley said, the bowl never emptied.

The possibility that the receptacle may have refilled itself during a March 5 service has kindled fascination among the faithful. It has also inspired the Archdiocese of Hartford to launch an investigation, which has since been sent to the highest echelons of the church hierarchy for review. If the Vatican finds that the reported increase in Communion hosts defies rational or scientific explanation, the conclusion could bolster Catholics’ belief in the teaching that the sacramental wafers literally become Jesus.

The probe could take months or years, so the parishioners of St. Thomas Church are relying for now on the proclamation of their pastor. Standing before his congregation in the 7,400-person town of Thomaston, Conn., Crowley said the reported miracle was evidence that God provides.

“Very powerful, very awesome, very real, very shocking – but also, it happens. It happens,” he said moments after the incident. “And today, it happened.”

The multiplication of hosts, if verified, would bolster efforts by the U.S. bishops to renew Catholics’ belief in the “daily miracle” of the wafers becoming Jesus’ body during the Mass, the archdiocese said.

“Through the centuries this daily miracle has sometimes been confirmed by extraordinary signs from Heaven, but the Church is always careful to investigate reports of such signs with caution, lest credence is given to something that proves to be unfounded,” the archdiocese said in a statement.

Ken Santopietro, a religious education teacher at St. Thomas, attended the Mass where the potential miracle occurred and was interviewed by representatives of the archdiocese. He recalled telling them that the people distributing Communion huddled with the priest afterward as if something unusual were happening.

Moments later, Crowley announced that the hosts had multiplied.

“I immediately believed in what he said he saw because of the reaction of not only him, but because of the group of people who were there – his ministers,” said Santopietro, who directs the Connecticut Catholic Men’s Conference.

Miracles are foundational to Catholicism, which teaches that Jesus was God in human form, worked miracles during his life and then died for humanity’s sins before rising from the dead. As the church defines it, a miracle is a sign or wonder that can only be attributed to God – “a glimpse into heaven,” said the Rev. Dorian Llywelyn, incoming director of the Center for Ignatian Spirituality at Loyola Marymount University.

When the church acknowledges a miracle, believers flock to the site to see evidence and reinvigorate their faith. Millions of Catholics each year travel to Fátima, Portugal, and Lourdes, France – both places where the Virgin Mary has reportedly appeared to people – among other locations.

St. Thomas would probably also attract visitors if it were declared the site of a miracle, said Michael O’Neill, author of “Science and the Miraculous: How the Church Investigates the Supernatural.” If the Vatican finds the multiplication claim to be credible, he said, they would encourage the church to display the leftover hosts in a small shrine.

The parish distributed some of the remaining wafers after the occurrence but saved others, Crowley told his congregation. He did not respond to an interview request from The Washington Post.

For the Catholic Church, investigating a supposed miracle is a rigorous process that often solicits input from scientists, doctors and other experts in their fields. The church relies on the technology available at the time, and experts said some occurrences deemed miracles years ago might not be understood that way if they were investigated today.

In Connecticut, the case of the multiplying hosts has parallels to the biblical story of loaves and fishes, in which Jesus is said to have used five loaves of bread and two fish to feed 5,000 men. The probe probably centers on the testimony and credibility of witnesses – the person distributing Communion from that bowl and anyone else who may have seen what happened.

Church officials will be interested in whether someone could have refilled the receptacle without the distributor noticing or whether that person may have not seen how many hosts were there in the first place, Llywelyn said. They will try to ensure that any witnesses are of sound mind and not seeking publicity.

Church officials may also review any available video and test the remaining wafers for differences in composition between them and other Communion hosts, O’Neill said.

The Archdiocese of Hartford was the first to investigate the potential miracle; whether it drew a conclusion is unclear. Elliott told the Catholic publication OSV News that the probe was led by the archdiocesan judicial vicar, who is tasked with judging spiritual matters. Dioceses will draw from their communities if they need people with specific expertise to help with an investigation, O’Neill said.

The Vatican’s department for doctrine and matters of belief, the Dicastery for the Doctrine of the Faith, is reviewing the Hartford archdiocese’s investigation. The review will involve theologians and canon lawyers – people with expertise in internal church law – in discussing the archdiocese’s reports and mulling whether rational explanations have been thoroughly considered, Llywelyn said.

Experts who testify about possible miracles before the Vatican are paid for their time, said hematologist and historian Jacalyn Duffin, who was questioned by church representatives about a potential miracle in the 1980s. Additional scholars are also brought in to offer feedback on experts’ testimony. Firsthand witnesses are not paid, because money could bias their testimony.

“At one level, there’s a hope that this will be an attested miracle, so there’s a degree of emotional involvement in that,” Llywelyn said. “The canonical process wants to take a step back from that fervor and not to get swayed by emotion, even good emotion.”

The Vatican ultimately will advise the Archdiocese of Hartford about whether it considers the possible multiplication of hosts definitely, maybe or absolutely not a miracle. The local bishop will then make and announce a final decision.

Even if the church decides that the event has a rational explanation, Catholics are free to believe personally that it was a miracle. Conversely, Catholics are not obligated to believe it was a miracle if the bishop declares it.

“Even in the most famous cases of modern miracles, you can walk away and ignore them if you find them annoying or distracting,” O’Neill said.

The Vatican questioned Duffin, the hematologist, about a potential miracle when the church was considering canonizing Marguerite d’Youville, who later became the first Canadian-born saint. Duffin recalled church officials asking her how a patient with aggressive acute leukemia had gone into remission after relapsing – then a virtually unheard of outcome.

The church representatives seemed wary of seeing a miracle where one might not exist, Duffin said. Still, she told them she could not think of a scientific reason for the patient’s survival.

“They wanted me to explain it,” said Duffin, author of “Medical Miracles: Doctors, Saints and Healing in the Modern World.” “And that really impressed me because I was naive about what the church did when it looks at these kinds of things. They are quite open to scientific explanation.”

Other types of miracles involve apparitions, stigmata – wounds that appear on parts of the body corresponding with the crucifixion of Jesus – and corpses that are said to be incorruptible, meaning they don’t decay as expected. In Missouri, pilgrims are converging on a monastery for religious sisters as word has spread that the exhumed remains of the order’s founder appear to have been miraculously preserved.

The church has recognized roughly 100 miracles involving Communion throughout its history, said O’Neill, who maintains a database of miracles acknowledged by the church. None have involved multiplying hosts, nor have any happened in the United States.

In some instances that the church has found credible, Communion hosts appear to bleed or develop an image resembling Jesus crowned with thorns. The church has deemed miracle claims unfounded in other cases, including when a red substance that appeared on a host in Utah was determined to be mold.

Some have speculated that the potential miracle in Connecticut could bolster the sainthood cause of Michael McGivney, a 19th-century pastor at St. Thomas and founder of the Catholic fraternal service organization Knights of Columbus. Another miracle attributed to him would precipitate his canonization.

Communion miracles, however, are infrequently relied upon in canonization efforts because the ease of comparing medical records from before and after makes healing miracles simpler to investigate. Attributing the possible Connecticut miracle to McGivney also would require someone to have prayed to him for something of its kind to happen.

Crowley told his congregation that neither he nor the person who distributed Communion had been praying for a multiplication of hosts. He asked his parishioners to tell him if they had been asking McGivney for help.

“Maybe Blessed McGivney interceded for us and God allowed this big thing to take place and to be made visible, to be made known,” Crowley said.

The Knights of Columbus, which pushes for sainthood for McGivney, did not respond to requests for comment on whether they might cite the occurrence at St. Thomas in their advocacy.

To some, whether the alleged multiplication is deemed a miracle is only important insofar as it strengthens people’s faith. Llywelyn said whether there’s a rational explanation for the apparent increase in Communion hosts is less important to him than whether people are more loving, tolerant and interested in justice because they believe the occurrence was a miracle.

“I’m not dissing the materiality, because the increase in faith has to be based in something,” Llywelyn said. “But I’m as interested, if not more interested, in the aftereffects.”